Sheet metal part, in particular of an exhaust gas system

ABSTRACT

The present invention relates to a sheet metal component ( 1 ), in particular of an exhaust system, having a body ( 2 ) comprising at least two shells ( 3, 4 ), having at least one pipe ( 5 ), wherein at least two shells ( 3, 4 ) are joined together along butt edges ( 8, 9 ) that are in contact, wherein at least two shells ( 3, 4 ) form a tubular connecting area ( 10 ) in contact with the pipe ( 5 ) on the outside, into which the butt edges ( 8, 9 ) of the shells ( 3, 4 ) that have been joined together extend, wherein the pipe ( 5 ) is joined to these shells ( 3, 4 ) by a welded seam ( 11 ) which extends along an edge ( 12 ) of the shells ( 3, 4 ) in the connecting area ( 10 ), running around the pipe ( 5 ) on the end with regard to the longitudinal direction ( 13 ) of the pipe. 
     To improve the durability of the sheet metal component ( 1 ), the shells ( 3, 4 ) are designed in the connecting area ( 10 ) so that they protrude beyond a longitudinal end ( 14 ) of the butt edges ( 8, 9 ) in the longitudinal direction ( 13 ) of the pipe ( 5 ) and are spaced a distance apart from one another.

The present invention relates to a sheet metal part, in particular of anexhaust gas system.

In a number of applications, sheet metal parts having a body comprisingat least two shells and at least one pipe are used. For example,housings manufactured in the half-shell type of construction with a pipeleading out of the housing are conceivable. The half-shells are thenjoined together along butt edges, e.g., by a welded seam. Thehalf-shells may form a tubular connecting area that is in contact withthe pipe on the outside for connection of the pipe in which the buttedges of the half-shells that are joined together extend. The pipe maythen be joined to the half-shells by a welded seam, such that thiswelded seam extends along an edge of the shells surrounding the pipe inthe connecting area, said edge being on the end with respect to thelongitudinal direction of the pipe. This edge on the end usually runsaround the pipe by the shortest path and is thus usually in a planeextending perpendicular to the longitudinal direction of the pipe. Inthe case of a circular cross section of the pipe, the edge on the endthus has a circular course, so that the welded seam is also circularbetween the pipe and the half-shells.

It has been found that high loads occur during operation of vehiclesequipped with exhaust gas systems in particular and may result infailure of the welded joint between the pipe and the shell body.

The present invention relates to the problem of providing an improvedembodiment for a sheet metal component of the type defined in theintroduction such that this embodiment is characterized in particular bythe fact that it has an increased lifetime.

This problem is solved according to the invention by the subject matterof the independent claim. Advantageous embodiments are the subjectmatter of the dependent claims.

The invention is based on the general idea of lengthening the shellswhich are in contact with the pipe in the connecting area beyond alongitudinal end of the adjacent butt edges in the longitudinaldirection of the pipe in such a way that the areas of the shellsprotruding beyond the longitudinal end of the butt edges are spaced adistance apart from one another. In a view from the side, this yields awedge-shaped or valley-shaped pattern for the end edge in which this endedge approaches the longitudinal end along its course from an area ofone shell at a distance from the longitudinal end of the butt edges andis again at a distance from the longitudinal end on the other shell. Dueto the proposed embodiment of the shells in the connecting area, thisyields an extension of the welded seam in proximity to the longitudinalend of the butt edges, which increases the connecting forces between thepipe and the shells or at least distributes the forces more uniformly.At the same time, this reduces the stress peaks in the area of thelongitudinal end of the butt edges, which lowers the total load on thewelded seam in the area of the longitudinal end. Accordingly, thedurability of the welded joint between the pipe and the shell body isthereby increased.

An embodiment in which the end edge on the two shells has a symmetricalcourse at least in a section starting from the longitudinal end of thebutt edges is advantageous. Due to the symmetry of the welded seam, themost uniform possible stress distribution within the welded seam underloads can be implemented.

According to another advantageous embodiment, the distance between thetwo shells in the connecting area may increase with an increase in thedistance from the longitudinal end of the butt edges. This implementsthe smoothest possible transition between the part of the welded seamleading past the longitudinal end of the butt edges and the parts of thewelded seam which are in the sections of the shells remote from thelongitudinal end. This also leads to a reduction in stress peaks withinthe welded seam.

In another advantageous embodiment, it is also possible to provide forthe two shells to be shaped in the connecting area so that a tangent tothe course of the end edge in the longitudinal end of the butt edgesruns perpendicular to the longitudinal direction of the butt edges. Thisdesign also achieves a reduction in stress peaks, especially in the areaof the longitudinal end.

Other important features and advantages of the invention are derivedfrom the dependent claims, the drawings and the respective descriptionof the figures on the basis of the drawings.

It is self-evident that the features mentioned above and those yet to bedescribed below may be used not only in the particular combination givenbut also in other combinations or alone without going beyond the scopeof the present invention.

Preferred exemplary embodiments of the invention are depicted in thedrawings and explained in greater detail in the following description,where the same reference numerals refer to the same or similar orfunctionally identical components.

They each show schematically:

FIGS. 1 through 5 each show a greatly simplified side view of a sheetmetal component in the area of a welded joint between a pipe and a shellbody in various embodiments.

According to FIGS. 1 through 5, a sheet metal component 1, which maypreferably be a component of an exhaust system, comprises a body 2,which consists of at least two shells 3 and 4 and may also be referredto below as a shell body 2. It is clear that the body 2 may also consistof more than two shells 3, 4. If there are only two shells 3, 4 present,they may be half-shells, but that is not absolutely necessary. Theshells 3, 4 are molded sheet metal parts, i.e., made of metal.Furthermore, the sheet metal component 1 has at least one pipe 5, whichis connected by a welded joint 6 to the shell body 2. It is clear thatthe sheet metal component 1 may essentially also have two or more suchpipes 5, which may be connected to the shell body 2 via correspondingwelded joints 6. The pipe 5 is also made of metal.

The two shells 3, 4 shown here each have a butt edge 8 and/or 9 along adividing line 7. In the assembled state, the two butt edges 8, 9 are incontact with one another along the dividing line 7. Furthermore, the twoshells 3, 4 are joined together along their butt edges 8, 9, which arein contact with one another. To this end, a welded seam which is notshown in greater detail here may also be provided. Essentially, the buttedges 8, 9 may also be joined together by flanging.

The two shells 3, 4 form a tubular connecting area 10, which issymbolized here by curly brackets. In this connecting area 10, theshells 3, 4 are in surface contact with the pipe 5 on the outside. Thebutt edges 8, 9 extend into one another in this connecting area 10.

The pipe 5 is connected to the shell body 2 via the welded joint 6. Tothis end, the welded joint 6 comprises a continuous welded seam 11,extending in the connecting area 10 along an edge 12 of the shells 3, 4,which surrounds the pipe 5 and is designed with regard to a longitudinaldirection 13 of the pipe 5 at the end.

The dividing line 7 along which the two butt edges 8, 9 are in contactwith one another defines a longitudinal direction of the butt edges 8,9. The butt edges 8, 9 end in the connecting area 10 at a longitudinalend 14. According to the invention the two shells 3, 4 are designed inthe connecting area 10 so that they each protrude beyond thelongitudinal end 14 in the longitudinal direction 13 of the pipe 5 andare spaced a distance apart from one another. To this end, the edge 12at the end has the wavy pattern, which is shown here in a side viewwhere the valley of the curve comes in contact with the longitudinal end14 of the butt edges 8, 9. Since the welded seam 11 extends along theend edge 12, the welded seam 11 follows this specific curve of the edge12. Due to this design of the shells 3, 4, the welded seam 11 is longerthan a welded seam which surrounds the pipe 5 along a plane running at aright angle to the longitudinal direction 13. The strength of the weldedjoint 6 can be increased by this measure alone. However, the shaping ofthe shells 3, 4, which is performed in a targeted manner in the area ofthe longitudinal end 14, leads at the same time to a significantrelaxation of tension on the welded seam 6 in the area of thelongitudinal end 14 because through this measure the forces to betransferred from the pipe 5 to the shells 3, 4 are distributed over alarger area. The durability of the welded joint 6 can be increased inthis way.

The sections of the shells 3, 4 protruding beyond the longitudinal end14 of the butt edges 8, 9 are also referred to below as protrusions 15and/or 16.

In the examples shown here, the end edge 12 has a symmetrical course. Inparticular the edge 12 and thus also the welded seam 11 are designedwith mirror symmetry with respect to a plane in which the dividing line7 is situated at least in the connecting area 10.

In the embodiments illustrated here, it is noteworthy that in theconnecting area 10, the distance between the protrusions 15, 16increases with an increase in the distance from the longitudinal end 14.This yields the wedge shape of the clearance formed between theprotrusions 15, 16 tapering in the direction of the longitudinal end 14.It is possible in this way to achieve a gradual transition in the courseof the edge 12 and thus the welded seam 11 between the area assigned tothe longitudinal end 14 and the areas at a distance from that.

In FIG. 1, a tangent 17 has also been drawn to the curve of the end edge12 and extends through the longitudinal end 14. This tangent 17 extendsperpendicular to the longitudinal direction, which has the butt edges 8,9 at least in the connection area 10. In this way, the stresses withinthe welded seam 11 can be reduced in the area of the longitudinal end14. For this purpose, the two shells 3, 4 may be shaped in the area oftheir protrusions 15, 16 so that the course of the edge 12 in the areaof the longitudinal end 14 has an arc segment of a circle. The radius ofthis arc segment of the circle may have, for example, 10% of thediameter 18 of the pipe 5, at least in the connecting area 10. Merely asan example and without any restriction on general validity, this radiusmay be 5 mm, for example.

The edge 12 may be a distance of up to a distance 19 away from thelongitudinal end 14 within the protrusions 15, 16, for example. Thisdistance 19 may amount to one-third of the diameter 18, for example.

The embodiments according to FIGS. 1 and 2 differ only in the design ofthe shell body 2. FIG. 1 shows an embodiment in which the sheet metalcomponent 1 may be, for example, a pipe assembly or a pipe branch, whichmay be designed in the manner of a Y-hose or an X-hose, for example. Incontrast with that, FIG. 2 shows an embodiment in which the sheet metalpart 1 may be a catalyst or a particulate filter or a muffler. Inaddition, any other embodiments are also conceivable for the sheet metalcomponent 1, e.g., an exhaust bend in the shell design and the like,such that not only may sheet metal components 1 be considered ascomponents of an exhaust system, but also fundamentally any otherapplications are also conceivable.

In the embodiments according to FIGS. 3 through 5, another pipe 20,which is connected to the other pipe 5 via another welded joint 21 isalso inserted into the pipe 5. The exterior pipe 5 is also referred tobelow as the outer pipe 5, while the interior pipe 20 is also referredto below as the inner pipe 20. The additional welded joint 21 joiningthe two pipes 5, 20 together comprises a peripheral welded seam 22 whichjoins an axial end 23 of the outer pipe 5 to the outside of the innerpipe 20. The inner pipe 20 and the outer pipe 5 may also be exchanged.

In the embodiment shown in FIG. 3, the outer pipe 5 extends onlyslightly beyond the end edge 12 of the shell body 2. This yields thepossibility of designing the two welded seams 11 and 22 as two-plate lapseam in at least some areas. This two-plate lap seam also has an overlapin the marked area 24 at the part of the welded seam 11 which leads tothe longitudinal edge 14 and returns back from that.

In the embodiment shown in FIG. 4, the outer pipe 5 protrudescomparatively far beyond the end edge 12 of the shell body 2, so thatthe two welded seams 11, 22 may be designed to be completely separatefrom one another.

In the embodiment shown in FIG. 5, the axial end 23 of the outer pipe 5expediently has the same course as the end edge of the shell body 2.This leads to the possibility of welding the inner pipe 20, the outerpipe 5 and the shell body 2 to one another with a common three-plate lapseam. The individual welded seams 11, 22 coincide with this; likewisethe welded joints 6, 21. In the side view shown in FIG. 5, the axial end23 of the outer pipe 5 is designed to coincide with the protrusions 15,16 of the shell body 2.

1. A sheet metal component for an exhaust system comprising: a bodycomprising at least two shells wherein the at least two shells includebutt edges; at least one pipe; a tubular connecting area created by theat least two shells, the connecting area adjacent to the pipe on theoutside; and a welded seam extending along an edge of the at least twoshells in the connecting area, the edge surrounding the pipe on an endof the pipe with regard to the longitudinal direction of the pipe;wherein the at least two shells are joined together along the butt edgesand are in contact with one another; wherein the interconnected buttedges of the at least two shells extend into the connecting area;wherein the pipe is connected to the at least two shells by the weldedseam; wherein the at least two shells protrude in the connecting areaover a longitudinal end of the butt edges in the longitudinal directionof the pipe and are spaced a distance apart from one another.
 2. Thesheet metal component according to claim 1, characterized in that theedge of the at least two shells has a symmetrical course at least in asection which leads away from the longitudinal end of the butt edges. 3.The sheet metal component according to claim 1, characterized in that inthe connecting area the distance between the at least two shellsincreases with an increase in the distance from the longitudinal end ofthe butt edges.
 4. The sheet metal component according to claim 1,characterized in that the at least two shells are shaped in theconnecting area so that a tangent to the curve of the end edge in thelongitudinal end of the butt edges runs at a right angle to thelongitudinal direction of the butt edges.
 5. The sheet metal componentaccording to claim 1, characterized in that the at least two shells areshaped in the connecting area so that the curve of the end edge has anarc-shaped segment in the area of the longitudinal end of the buttedges.
 6. The sheet metal component according to claim 1, characterizedin that the at least two shells protrude approximately one-third of thediameter of the pipe beyond the longitudinal end of the butt edges inthe connecting area.
 7. The sheet metal component according to claim 1,characterized in that another pipe which is connected by a peripheralwelded seam to an axial end of the outer pipe is inserted into the pipe.8. The sheet metal component according to claim 7, characterized in thatthe axial end of the outer pipe is shaped to be run in the same way asthe curve of the end edge of the at least two shells.
 9. The sheet metalcomponent according to claim 7, characterized in that the welded seamfor connecting the inner pipe to the outer pipe and the welded seam forconnecting the outer pipe to the at least two shells are designed as atwo-plate lap seam or as a three-plate lap seam.
 10. The sheet metalcomponent according to claim 1, characterized in that the sheet metalcomponent is one of a shell bend, a catalytic converter, a particulatefilter, a muffler, a pipe assembly and a pipe branch.
 11. The sheetmetal component according to claim 2, characterized in that the sheetmetal component is one of a shell bend, a catalytic converter, aparticulate filter, a muffler, a pipe assembly and a pipe branch. 12.The sheet metal component according to claim 2, characterized in that inthe connecting area the distance between the at least two shellsincreases with an increase in the distance from the longitudinal end ofthe butt edges.
 13. The sheet metal component according to claim 2,characterized in that the at least two shells are shaped in theconnecting area so that a tangent to the curve of the end edge in thelongitudinal end of the butt edges runs at a right angle to thelongitudinal direction of the butt edges.
 14. The sheet metal componentaccording to claim 2, characterized in that the at least two shells areshaped in the connecting area so that the curve of the end edge has anarc-shaped segment in the area of the longitudinal end of the buttedges.
 15. The sheet metal component according to claim 2, characterizedin that the at least two shells protrude approximately one-third of adiameter of the pipe beyond the longitudinal end of the butt edges inthe connecting area.
 16. The sheet metal component according to claim 2,characterized in that another pipe which is connected by a peripheralwelded seam to an axial end of the outer pipe is inserted into the pipe.17. The sheet metal component according to claim 3, characterized inthat the at least two shells are shaped in the connecting area so that atangent to the curve of the end edge in the longitudinal end of the buttedges runs at a right angle to the longitudinal direction of the buttedges.
 18. The sheet metal component according to claim 3, characterizedin that the at least two shells are shaped in the connecting area sothat the curve of the end edge has an arc-shaped segment in the area ofthe longitudinal end of the butt edges.
 19. The sheet metal componentaccording to claim 3, characterized in that the at least two shellsprotrude approximately one-third of the diameter of the pipe beyond thelongitudinal end of the butt edges in the connecting area.
 20. The sheetmetal component according to claim 8, characterized in that the weldedseam for connecting the inner pipe to the outer pipe and the welded seamfor connecting the outer pipe to the at least two shells are designed asa two-plate lap seam or as a three-plate lap seam.